Apparatus for the recovery of precious metals.



PATENTED AUG. 11, 1903.

APPLICATION FILED MAY 23, 1903.

H. L. SULMAN & H. F. KIRKPATRIGK-PIGARD. APPARATUS FOR THE RECOVERY OFPRECIOUS METALS- 0 MODEL.

THE NORRS ET NlTED STATES Patented August 11, 1903.

PATENT OFFICE.

HENRY LIVINGSTONE SULMAN AND HUGH FITZALIS KIRKPATRICK-PIOARD,

OF LONDON, ENGLAND.

APPARATUS FOR THE RECOVERY OF PRECIOUS METALS.

SPECIFICATION forming part of Letters Patent NO. 736,036, dated August11, 1903.

Application filed May 23, 1903. Serial No. 158,517. (No model.)

T aZZ whom it may concern:

Be it known that we, HENRY LIVINGSTONE SULMAN and HUGH FITZALISKIRKPATRICK- PICARD, subjects of the King of England, re-

siding at London, England, have invented certain new and usefulImprovements in or Relating to the Recovery of Precious Metals, of whichthe following is a specification.

The present invention relates to an imro proved method and apparatus forthe recovery of precious metals from liquids containing them either insolution or suspension.

According to this invention the sufficiently finely ground ores or pulpsmixed with a solvent or leached, filtered, or decanted solutionscontaining the values are passed up through a continuous vertical orinclined column, film, or sheet of mercury kept continuously chargedwith an electropositive metal, such as sodium, in order to decompose thecompounds of the precious metals presented to the so-prepared mercury.

In carrying out the process the mercury is conveniently contained in thenarrow interspace between two or more inclined or vertical surfaces, andin practice a convenient form of apparatus comprises a series of two ormore concentric inverted conical vessels, of which the center one may bea core, so arranged that an interspace of suitable width is maintainedbetween the inner surface of one vess'el'and the outer surface of thenext vessel. The vessels or cones are constructed of or covered withcopper or other suitable metal, and the metal surfaces being amalgamatedinsure the maximum contact between the ore or solvent passing upwardthrough the apparatus and the amalgam. Any other convenient formof-apparatus may be used-- 40 for example, vertical hollow concentriccylinders, plain or fluted, or a'vessel containing a number of smalltubes, rods, or baffles. In order to maintain the mercury in anefficient condition, a stream of sodium amalgam, preferably continuous,is run into the extraction apparatus, while a corresponding amount ofmercury depleted of electropositive metal is withdrawn. Such amalgam maybe prepared by any well-known electrolytic method, as by thedecomposition of an electrolyte-such assodiumchlorid,hydrate,orcarbonatewith a cathode of mercury, by theintroduction of metallic sodium into-mercury, or otherwise.v Theelectrolytic cell for preparing the desired amalgam may be separate fromand placed outside the extraction apparatus and may be of anysuitabletype, so arranged that mercury may becontinuously fed into it and thesodium or other amalgam produced there- I from continuously runoif intothe extraction 6o apparatus, or the electrolytic cell may be part of theextraction apparatus, and theelectrolyte is then separated from themercury amalgamby a porous diaphragm, such as a porous pot or cell orequivalent, the Whole being so arranged that the material undertreatment is not submitted to direct electrolysis, but that theelectropositive metal is continually deposited into the mercury from theelectrolyte.

The accompanying drawing is a perspective view, partly in section, ofone form of apparatus suitable for carrying out this invention.

On a base A is supported an inverted conical vessel B, of copper, andwithin it is a concentric copper cone 0, a narrow interspace D beingleft between the surfaces. The outer cone B is provided at the top witha launder E, having an outlet-pipe E, and the cone B terminates at thebottom in an inlet B, attached to a sleeve F. The apex of the inner cone0 rests in a hollow socketG, which is carried on an externally-screwedtube F, which engages the inside of the sleeve F, and by screwing thetube F within the sleeve F the socket G and inner cone 0 can be raisedor lowered and the distance between the cones varied. Apertures G areprovided in the sides of the socket to allow of free pas- 9'0 sage ofliquid through the socket G, which thus acts also as a distributor. Thelaunder E carries a frame H, in which is screwed a central vertical pinJ, serving as a support for the inner cone 0, and for this purpose thecone 0 has an axis 0, rigidly held in the center of the cone by stays Gand'engaging with the pin J. When adjusting the inner cone 0 inposition, the pin J can be correspondingly screwed up or down. The tubeF is too attached to a union K, which is connected, through a non-returnvalve L and a pump, with suitable mixing or dissolving apparatus.

At the top of the inner cone 0 is a mercury-distributing cup 0, havingoutlet-tubes O, which conduct mercury to the interspace between thecones B O at any convenient height below the normal working level of themercury between the cones, a groove 13 being formed on the outer cone Bat the level of the mercury-inlet. The mercury is supplied to the cup 0through a pipe P from an electrolytic vessel P and may be fed eitherfrom the inside, as shown, or from the outside. The mercury Q in theelectrolytic vessel forms the cathode of the circuit of an electrolyticbattery S or other source, the anode being a conducting-plate T,immersed in the electrolyte R. The mercury is removed from the bottom ofthe cone B through an outlettap U, connected with a pump U, whichdischarges the mercury into the vessel P. A gage-glass B is provided onthe outer cone B to indicate the height of the mercury.

The operation of the apparatus is as follows: The mercury is chargedwith metallic sodium in the electrolytic vessel and is conducted throughthe pipe P, distributer O, and tubes 0 to the interspace D between thecones B C and completely fills the space D approximately to the level ofthe groove B The sufficiently finely ground ore or slimes, mixed orpreviously treated with a solvent, such as potassium cyanid, are forcedbya suitable pump through the valve L into the pipe F and up through theinterspace' D containing sodium'amalgam, with the result that the doublecyanid of precious metal and potassium or other precious-metal compoundsheld in solution are decomposed and the precious metal is retained bythe mercury as an amal garn. At the same time any undissolved particlesof free gold after these have been sub mitted to the action of thesolvent are also recovered. Astream of the sodium mercury is passed intothe apparatus, as above described, and an equal quantity of mercurypartially free from sodium, but now carrying values, is withdrawnthrough the tap U and returned by the pump U to the electrolyticapparatus P to be recharged with fresh sodium and again returned to theapparatus, and so on until the mercury is sufiiciently rich in preciousmetals to be withdrawn from the cycle of operations for the recovery bydistillation, filtration, or the like of the contained precious metals.By this process of treatment filter-pressing or decantation is avoided,as is also zinc-box precipitation.

The apparatus may comprise more than two conical vessels or may beotherwise arranged to secure the distribution factor given by cones. Thevertical angle of the cones may be as great as desired or the apparatusmay be flat; but as hydrogen is apt to collect under the upperamalgamated plate in a flat apparatus placed horizontally it ispreferable to use cones or other surfaces so shaped that the hydrogengenerated tends to escape from between them. The mercury may be chargedwith sodium otherwise than by electrolysis.

This process is also applicable to the recovery of precious metals fromsolutions that have been removed by previous filtration or decantationfrom crushed ore or slimes.

In the treatment of some solutions and of some ores suspended therein itmay be advantageous to put the mercury in circuit with an electriccurrent in such manner that no electrolysis of the solutions containingthe precious metals can take place but with the object of keeping themercury amalgam in a highly efficient and active condition. If desired,the solution may be fed in through a central tube.

What we claim as our invention, and desire to secure by Letters Patent,is-

1. In an apparatus for recovering precious metals the combination of avessel having an inner amalgamated surface, a body having its outersurface amalgamated disposed within the vessel and forming therewith anarrow interspace, a body of mercury continuously charged with anelectropositive metal in the interspace, and means for forcing thesolution carrying the values upward through the interspace.

2. In an apparatus for recovering precious metals the combination of avessel having an inner amalgamated surface, a body having its outersurface amalgamated disposed within the vessel and forming therewith anarrow interspace, a body of mercury charged with an electropositivemetal in the interspace, an apparatus for charging the mercury with theelectropositive metal, an inlet conduit for mercury from said apparatusto the top of the interspace, an outletconduit for mercury from thebottom of the interspace to said apparatus, and means for forcing thesolution carrying the values upward through the interspace.

3. In an apparatus for recovering precious metals the combination of avessel having an inner amalgamated surface, a body having its outersurface amalgamated disposed within the vessel and forming therewith anarrow interspace, a body of mercury charged with an electropositivemetal in the interspace, an apparatus for charging the mercury with theelectropositive metal, an inlet-conduit for mercury from said apparatusto the top of the interspace, an outletconduit for mercury from thebottom of the interspace to said apparatus, an inlet-conduit at thebottom of the vessel for the solution carrying the values, anoutlet-conduit at the top of the vessel for solution, and means forforcing the solution upward through the interspace.

4. In an apparatus for recovering precious metals the combination of avessel having an inner amalgamated surface, a body having its outersurface amalgamated disposed Within the vessel and forming therewith anarrow IIIO interspace, means for varying the interspace, a body ofmercury charged with an electropositive metal in the interspace, anapparatus for charging the mercury with the electropositive metal, aninlet-conduit for mercury from said apparatus to the top of theinterspace, an outlet-conduit for mercury from the bottom of theinterspace to said apparatus, an inlet-conduit at the bottom of thevessel for the solution carrying the values, an out let-conduit at thetop of the vessel for solution, and means for forcing the solutionupward through the interspace.

5. In an apparatus for recovering precious metals the combination of aconical vessel having an inner amalgamated surface, a conical bodyhaving an outer amalgamated surface disposed concentrically within thevessel and forming therewith a narrow interspace, a body of mercurycontinuously charged with an electropositive metal in the interspace,and means for forcing the solution carrying the values up through theinterspace.

6. In an apparatus for recovering precious metals the combination of aconical vessel havingan inneramalgamated-copper surface, a conical bodyhaving an outer amalgamatedcopper surface disposed concentrically withinthe vessel and forming therewith a narrow interspace, a body of mercurycontinuously charged with an electropositive metal in the interspace,and means for forcing the solution carrying the values up through theinterspace.

7. In an apparatus for recovering precious metals the combination of aconical vessel havinganinner amalgamated-coppersurface, a conical bodyhaving an outer amalgamatedcopper surface disposed concentrically withinthe vessel and forming therewith a narrow interspace, a body of mercurycharged with an electropositive metal in the interspace, an electrolyticvesssel for charging the mercury, a mercury-pump, an inlet-conduit tothe top of the interspace from the electrolytic vessel, anoutlet-conduit for mercury from the bottom of the interspace to thepump, a conduit from the pump to the electrolytic vessel, and means forforcing the solution carrying the values up through the interspace.

8. In an apparatus for recovering precious metals the combination of aconical vessel having aninneramalgamated-copper surface, a conical bodyhaving an outer amalgamatedcopper surface disposed concentrically withinthe vessel and forming therewith a narrow interspace, a body of mercurycharged with an electropositive metal in the interspace, an electrolyticvessel for charging the mercury, a mercury-pump, an inlet-conduit to thetop of the interspace from the electrolytic vessel, an outlet-conduitformercury from the bottom of the interspace to the pump, aconduit fromthe pump to the electrolytic vessel, an inlet-conduit at the bottom ofthe vessel for the solution carrying the values, means for forcing thesolution up through the interspace, and a launder at the top of thevessel to receive the discharged solution.

9. In an apparatus for recovering precious metals the combination of aconical vessel having an inner am algamated-copper surface, a conicalbody having an outer amalgamatedcopper surface disposed concentricallywithin the vessel and forming therewith a narrow interspace, a body ofmercury charged with an electropositive metal in the interspace, anelectrolytic vessel for charging the mercury, a mercury-pump, aninlet-conduit to the top of the interspace from the electrolytic vessel,an outlet-conduit for mercury from the bottom of the interspace to thepump, aconduit from the pump to the electrolytic vessel, aninlet-conduit at the bottom of the vessel for the solution carrying thevalues, a non-return valve in said conduit, means for forcing thesolution up through the interspace, and a launder at the top of thevessel to receive the discharged solution.

'10. In an apparatus for recovering precious metals the combination of aconical vessel having an inneramalgamated-coppersurface,

a conical body having an outer amalgamated-' copper surface disposedconcentrically within the vessel and forming therewith a narrowinterspace, means for vertically moving the inner cone to vary theinterspace, a body of mercury charged with an electropositive metal inthe interspace, an electrolytic vessel for charging the mercury, amercury-pump,

an inlet-conduit to the top of the interspace from the electrolyticvessel an outlet-conduit for mercury from the bottom of the interspaceto the pump, a conduit from the pump to the electrolytic vessel, aninlet-conduit at the bottom of the vessel for the solution carrying thevalues, a non-return valve in said In testimony whereof we have signedour names to this specification in the presence of two subscribingwitnesses.

HENRY LIVINGSTONE SULMAN. HUGH FlTZALlS KIRKPATRIOK-PIOARD.

Witnesses:

CLAUDE MCKENZIE, G. O. WILLIAMS.

